Receive, maintain, and experimentally use rodents (largely mice). Propagate and maintain tumor stock in vivo. Prepare materials for testing. Administer test materials to tumor-bearing animals. Measure test activity using specified parameters of effects. Determine test material activity. Collect and summarize data as specified. Report results in the manner and frequency as specified in the contract. Upon specific request, test new and older active drugs to determine the influence of factors which might modify "activity" such as the formulation for injection (vehicles, physical state, pH, etc.), the treatment schedule, the route of administration, the site to tumor implantation, etc.